Presence and Availability Management (PAM) tools are available in the art to provide and expose presence information to users of PC-based interfaces. As is known in the art, such tools are common in Instant Messaging (IM) systems and may be applied to a variety of devices and contexts, including email systems, Personal Digital Assistants (PDA's), text-based or graphical/visual displays offered in cellular phones and Session Initiation Protocol (SIP) or other Voice Over Internet (VoIP) Phones.
The above applications generally include a text display to indicate presence and status information for members of a “buddy list” selected by the user. Typically, PAM users monitor the presence of other individuals, usually called “buddies”. The collection of buddies is usually called a buddy list. To date, audio only devices, such as traditional Public Switched Telephone Network (PSTN) telephones, have not provided presence information directly to users. While one's presence may be inferred from some telephones that can visually show the state of one or more telephone lines, typically, a PSTN user does not receive presence information until an attempt is made to place a call. The caller may then hear ringing, a busy signal, or a message intercepting the call; each alternative provides some evidence as to the called party's availability. As attested to by the popularity of IM services, it is desirable to provide presence and availability information to a PSTN user for members of a buddy list.